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Issues with March Pump

I’ve had my March pump for ~8 years now and never had any major issues with it. I run it on my custom 15 gal RIM system. Then two batches ago it started acting up towards the end. It does this thing where I turn it on, it starts and then within one second I hear it make a noise like it dips in power and then it basically acts like it’s lost prime and stops pumping. It happened at the end of a batch so I just moved some stuff around and (slowly) chilled through gravity feed. I tested it out with room temperature water a few days before my next brew and it worked fine for 10 min+ so I didn’t attempt to fix anything.

I brewed yesterday and it started acting up a little during recirc. It would do it’s weird thing about once every five minutes. Then I went to finish up and chill and same thing as last time–it would dip and lose prime after just a second.

I’ve heard of people replacing the impeller in these and it looks straight forward. I could do that but was wondering if anyone else has experienced something like this before I start dismantling. It’s attached to some hard piping that would be a semi-pain to remove. The problem almost acts like it’s an issue with the motor but it seems greatly influenced by fluid temperature.

Any thoughts?

Have you taken the pumphead off and given it a good cleaning? Check the impeller shaft too. There might be some gunk in there.

I have had that happen too and my impeller/magnet assembly was uncoupling from the motor. It only happens when I have a few gallons in my 25 gallon pot (less NPSHR) so to make it stop, I throttle back on the discharge valve. I have the 809HS pump with an 815 impeller in it.

[quote=“beeristhemindkiller”]The problem almost acts like it’s an issue with the motor but it seems greatly influenced by fluid temperature.[/quote]If the pump is failing as the temp increases, pull the impeller and clean off any build-up on the stator, see if that fixes the problem.

He will help you out.

Magnets get weaker at higher temps. Maybe your thrust washer is worn out and its dragging enough that at the higher temp it won’t go. You can buy a kit with the new impeller, thrust washer and oring on ebay. But certainly ask Walter first.

I have tried throttling it back and that didn’t work unfortunately. I started from 0% when I turned it on and slowly opened to 100%.

I’ve never taken the pump apart in all the years I’ve owned it but I have run plenty of sanitizer and cleaner through it. Like I said, it’s a bit of a pain to access and disassemble but I guess I should bite the bullet. Now I’m worried as to what I’ll find in there.

Thanks for the email address 'keg. I’ve heard of Walter before on older threads so I wasn’t sure if he was still around. I’ll give him a shout. If anyone knows, it’ll be him.

I heard back from Walter already. For any who are interested, here’s his reply:

There are two common problems I have come to find with home brewers. First is if the pumps are not cleaned out properly after each use then they can get a sugar buildup on the inside of the impeller and it hardens up. Next go round when you brew, when the temp rises up and the impeller expands a little bit, it will seize slightly on the shaft and the magnet will de-couple and you will loose all pumping action. The second issue is the Teflon thrust washer wears out and the impeller rubs up against the front housing also de-coupling the impeller.
The first problem can be solved by drilling out the impeller bore with a 17/64” drill bit. That will open it up a few thousands more and give more clearance for liquid to get in between the shaft and impeller.

The thrust washer issue can only be solved with a new one if it’s missing. I know a few guys have gone a found some washer locally at hardware stores. the washer is 13/32” wide…has a 1/4” hole to fit on the shaft…and its .032 (a little bigger than 1/32”) thick…if you can something fairly close then you should be good to go.

Walter’s the man for all things March! :cheers:

They are super easy to pull apart for an inspection and good cleaning.

Thanks for all the help yesterday, everyone. Fingers crossed that one of these things works.

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